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Subject[Part2 PATCH v5 19/31] KVM: SVM: Add support for KVM_SEV_LAUNCH_START command
Date
The KVM_SEV_LAUNCH_START command is used  to create a memory encryption
context within the SEV firmware. In order to create the memory encryption
context, the guest owner's should provide the guest's policy, its public
Diffie-Hellman (PDH) key and session information. The command implements
the LAUNCH_START flow defined in SEV spec Section 6.2.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86@kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
arch/x86/include/asm/kvm_host.h | 2 +
arch/x86/kvm/svm.c | 181 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 183 insertions(+)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 6bd49e80a16d..7453ef7cb487 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -750,6 +750,8 @@ enum kvm_irqchip_mode {
struct kvm_sev_info {
bool active; /* SEV enabled guest */
unsigned int asid; /* ASID used for this guest */
+ unsigned int handle; /* SEV firmware handle */
+ int fd; /* SEV device fd */
};

struct kvm_arch {
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index a1388e74149f..c599a87810af 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1551,11 +1551,45 @@ static void sev_asid_free(struct kvm *kvm)
}
}

+static void sev_unbind_asid(struct kvm *kvm, unsigned int handle)
+{
+ struct sev_data_decommission *decommission;
+ struct sev_data_deactivate *data;
+
+ if (!handle)
+ return;
+
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return;
+
+ /* deactivate handle */
+ data->handle = handle;
+ sev_guest_deactivate(data, NULL);
+
+ wbinvd_on_all_cpus();
+ sev_guest_df_flush(NULL);
+ kfree(data);
+
+ decommission = kzalloc(sizeof(*decommission), GFP_KERNEL);
+ if (!decommission)
+ return;
+
+ /* decommission handle */
+ decommission->handle = handle;
+ sev_guest_decommission(decommission, NULL);
+
+ kfree(decommission);
+}
+
static void sev_vm_destroy(struct kvm *kvm)
{
+ struct kvm_sev_info *sev = &kvm->arch.sev_info;
+
if (!sev_guest(kvm))
return;

+ sev_unbind_asid(kvm, sev->handle);
sev_firmware_exit();
sev_asid_free(kvm);
}
@@ -5638,6 +5672,149 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
return ret;
}

+static int sev_bind_asid(struct kvm *kvm, unsigned int handle, int *error)
+{
+ struct sev_data_activate *data;
+ int asid = sev_get_asid(kvm);
+ int ret;
+
+ wbinvd_on_all_cpus();
+
+ ret = sev_guest_df_flush(error);
+ if (ret)
+ return ret;
+
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ /* activate ASID on the given handle */
+ data->handle = handle;
+ data->asid = asid;
+ ret = sev_guest_activate(data, error);
+ kfree(data);
+
+ return ret;
+}
+
+static int sev_issue_cmd(int fd, int id, void *data, int *error)
+{
+ struct fd f;
+ int ret;
+
+ f = fdget(fd);
+ if (!f.file)
+ return -EBADF;
+
+ ret = sev_issue_cmd_external_user(f.file, id, data, error);
+
+ fdput(f);
+ return ret;
+}
+
+static void *copy_user_blob(u64 __user uaddr, u32 len)
+{
+ void *data;
+
+ if (!uaddr || !len)
+ return ERR_PTR(-EINVAL);
+
+ /* verify that blob length does not exceed our limit */
+ if (len > SEV_FW_BLOB_MAX_SIZE)
+ return ERR_PTR(-EINVAL);
+
+ data = kmalloc(len, GFP_KERNEL);
+ if (!data)
+ return ERR_PTR(-ENOMEM);
+
+ if (copy_from_user(data, (void __user *)(uintptr_t)uaddr, len))
+ goto e_free;
+
+ return data;
+
+e_free:
+ kfree(data);
+ return ERR_PTR(-EFAULT);
+}
+
+static int sev_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
+{
+ struct kvm_sev_info *sev = &kvm->arch.sev_info;
+ struct sev_data_launch_start *start;
+ struct kvm_sev_launch_start params;
+ void *dh_blob, *session_blob;
+ int *error = &argp->error;
+ int ret;
+
+ if (!sev_guest(kvm))
+ return -ENOTTY;
+
+ if (copy_from_user(&params, (void __user *)(uintptr_t)argp->data,
+ sizeof(struct kvm_sev_launch_start)))
+ return -EFAULT;
+
+ start = kzalloc(sizeof(*start), GFP_KERNEL);
+ if (!start)
+ return -ENOMEM;
+
+ dh_blob = NULL;
+ if (params.dh_uaddr) {
+ dh_blob = copy_user_blob(params.dh_uaddr, params.dh_len);
+ if (IS_ERR(dh_blob)) {
+ ret = PTR_ERR(dh_blob);
+ goto e_free;
+ }
+
+ start->dh_cert_address = __sme_set(__pa(dh_blob));
+ start->dh_cert_len = params.dh_len;
+ }
+
+ session_blob = NULL;
+ if (params.session_uaddr) {
+ dh_blob = copy_user_blob(params.session_uaddr, params.session_len);
+ if (IS_ERR(session_blob)) {
+ ret = PTR_ERR(session_blob);
+ goto e_free_dh;
+ }
+
+ start->session_address = __sme_set(__pa(session_blob));
+ start->session_len = params.session_len;
+ }
+
+ start->handle = params.handle;
+ start->policy = params.policy;
+
+ /* create memory encryption context */
+ ret = sev_issue_cmd(argp->sev_fd, SEV_CMD_LAUNCH_START, start, error);
+ if (ret)
+ goto e_free_session;
+
+ /* Bind ASID to this guest */
+ ret = sev_bind_asid(kvm, start->handle, error);
+ if (ret)
+ goto e_free_session;
+
+ /* return handle to userspace */
+ params.handle = start->handle;
+ if (copy_to_user((void __user *)(uintptr_t)argp->data, &params,
+ sizeof(struct kvm_sev_launch_start))) {
+ sev_unbind_asid(kvm, start->handle);
+ ret = -EFAULT;
+ goto e_free_session;
+ }
+
+ sev->handle = start->handle;
+ sev->fd = argp->sev_fd;
+
+e_free_session:
+ kfree(session_blob);
+e_free_dh:
+ kfree(dh_blob);
+e_free:
+ kfree(start);
+ return ret;
+}
+
static int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
{
struct kvm_sev_cmd sev_cmd;
@@ -5656,6 +5833,10 @@ static int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
r = sev_guest_init(kvm, &sev_cmd);
break;
}
+ case KVM_SEV_LAUNCH_START: {
+ r = sev_launch_start(kvm, &sev_cmd);
+ break;
+ }
default:
break;
}
--
2.9.5
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